Detailed Research Information

Detailed project information for
Study Plan Number 01072-07

Branch : Fish Health Branch

Study Plan Number : 01072-07

Study Title : Pathology and mortality associated with newly emergent fry from Penobscot and Downeast river stocks of Atlantic salmon

Starting Date : 05/01/1999

Completion Date : 09/30/2001

Principal Investigator(s) : Cipriano, Rocco C.

Primary PI : Cipriano, Rocco C.

Telephone Number : (304) 724-4432

Email Address : rocco_cipriano@usgs.gov

SIS Number : 5004523

Primary Program Element : Fisheries and Aquatic Resources

Second Program Element : Fish and Aquatic Habitats

Status : Completed

Abstract :
Federal restoration of Atlantic salmon in the northeastern United States concentrates principally upon enhancement of stocks within the Connecticut River, Merrimack River, Penobscot River and several smaller rivers on the Downeast coast of Maine. River-specific brood stocks are used to enhance the genetic integrity of the fish within each river system. Consequently, the gametes produced from the limited number of adult salmon returning to each of these river systems are extremely valuable in terms of providing a sufficient number of offspring to continue the restoration effort. In the course of study, chronic symptoms of Bacterial Coldwater Disease, caused by Flavobacterium psychrophilum, were noted among a proportion of offspring that are propagated and stocked as smolts. Classical peduncle lesions and chronic mortality were associated with the affected fish. The disease was more pronounced in salmon reared in two-year rather than one-year smolt production cycles. Following the identification of these symptoms, the pathogen was shown to be the etiologic agent of mortality among yolk-sac fry in Heath incubators, associated with reductions in egg viability, and indicated to be transmitted by intra-ovum infection.

Vertical transmission among fish can be defined as the passing of an infectious agent from a parent to an offspring via intraovum infection. Eggs from Atlantic salmon (Salmo salar) were examined to to test the hypothesis that F. psychrophilum can be vertically transmitted. Twenty matings were made with Atlantic salmon held at the Richard Cronin National Salmon Station (Sunderland, MA). Fertilized eggs were placed in 50 ppm iodine for 30 min, and water hardened for 60 min. Eggs were iced and shipped to the White River National Fish Hatchery (Bethel, VT), again disinfected in 100 ppm iodine for 10 min, and placed in Heath incubators receiving UV-treated well water. Before additional studies were conducted, eggs were again disinfected in 100 ppm iodine for 60 min. Flavobacterium psychrophilum was present among 9 lots pre-disinfection and pathogen concentrations ranged between 5.0x103 to 5.5x107 cfu/g of egg. Even after three disinfections, the pathogen was still cultured from 5 of these lots at concentrations between 7.1x102 to 6.1x107 cfu/g of egg. Isolates tested were directly suspended in and killed by a single incubation with 100 ppm iodine for 30 min. Flavobacterium psychrophilum was still recovered from eggs even after a total of three disinfections; one in 100 ppm iodine for 60 min, a concentration of iodophor that effectively killed the pathogen on direct contact in half the time. Data strongly indicate that F. psychrophilum can be vertically transmitted via intra-ovum infection. Federal restoration of Atlantic salmon in the northeastern United States concentrates principally upon enhancement of stocks within the Connecticut River, Merrimack River, Penobscot River and several smaller rivers on the Downeast coast of Maine. River-specific brood stocks are used to enhance the genetic integrity of the fish within each river system. Consequently, the gametes produced from the limited number of adult salmon returning to each of these river systems are extremely valuable in terms of providing a sufficient number of offspring to continue the restoration effort. In the course of study, chronic symptoms of Bacterial Coldwater Disease, caused by Flavobacterium psychrophilum, were noted among a proportion of offspring that are propagated and stocked as smolts. Classical peduncle lesions and chronic mortality were associated with the affected fish. The disease was more pronounced in salmon reared in two-year rather than one-year smolt production cycles. Following the identification of these symptoms, the pathogen was shown to be the etiologic agent of mortality among yolk-sac fry in Heath incubators, associated with reductions in egg viability, and indicated to be transmitted by intra-ovum infection. The pathogen, therefore, has a significant role in the production of quality gametes and may be an extremely important factor in the post-stocking survival of salmon fry and smolts.

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Branch :	Fish Health Branch
Study Plan Number :	01072-07
Study Title :	Pathology and mortality associated with newly emergent fry from Penobscot and Downeast river stocks of Atlantic salmon
Starting Date :	05/01/1999
Completion Date :	09/30/2001
Principal Investigator(s) :	Cipriano, Rocco C.
Primary PI :	Cipriano, Rocco C.
Telephone Number :	(304) 724-4432
Email Address :	rocco_cipriano@usgs.gov
SIS Number :	5004523
Primary Program Element :	Fisheries and Aquatic Resources
Second Program Element :	Fish and Aquatic Habitats
Status :	Completed
Abstract :	Federal restoration of Atlantic salmon in the northeastern United States concentrates principally upon enhancement of stocks within the Connecticut River, Merrimack River, Penobscot River and several smaller rivers on the Downeast coast of Maine. River-specific brood stocks are used to enhance the genetic integrity of the fish within each river system. Consequently, the gametes produced from the limited number of adult salmon returning to each of these river systems are extremely valuable in terms of providing a sufficient number of offspring to continue the restoration effort. In the course of study, chronic symptoms of Bacterial Coldwater Disease, caused by Flavobacterium psychrophilum, were noted among a proportion of offspring that are propagated and stocked as smolts. Classical peduncle lesions and chronic mortality were associated with the affected fish. The disease was more pronounced in salmon reared in two-year rather than one-year smolt production cycles. Following the identification of these symptoms, the pathogen was shown to be the etiologic agent of mortality among yolk-sac fry in Heath incubators, associated with reductions in egg viability, and indicated to be transmitted by intra-ovum infection. Vertical transmission among fish can be defined as the passing of an infectious agent from a parent to an offspring via intraovum infection. Eggs from Atlantic salmon (Salmo salar) were examined to to test the hypothesis that F. psychrophilum can be vertically transmitted. Twenty matings were made with Atlantic salmon held at the Richard Cronin National Salmon Station (Sunderland, MA). Fertilized eggs were placed in 50 ppm iodine for 30 min, and water hardened for 60 min. Eggs were iced and shipped to the White River National Fish Hatchery (Bethel, VT), again disinfected in 100 ppm iodine for 10 min, and placed in Heath incubators receiving UV-treated well water. Before additional studies were conducted, eggs were again disinfected in 100 ppm iodine for 60 min. Flavobacterium psychrophilum was present among 9 lots pre-disinfection and pathogen concentrations ranged between 5.0x103 to 5.5x107 cfu/g of egg. Even after three disinfections, the pathogen was still cultured from 5 of these lots at concentrations between 7.1x102 to 6.1x107 cfu/g of egg. Isolates tested were directly suspended in and killed by a single incubation with 100 ppm iodine for 30 min. Flavobacterium psychrophilum was still recovered from eggs even after a total of three disinfections; one in 100 ppm iodine for 60 min, a concentration of iodophor that effectively killed the pathogen on direct contact in half the time. Data strongly indicate that F. psychrophilum can be vertically transmitted via intra-ovum infection. Federal restoration of Atlantic salmon in the northeastern United States concentrates principally upon enhancement of stocks within the Connecticut River, Merrimack River, Penobscot River and several smaller rivers on the Downeast coast of Maine. River-specific brood stocks are used to enhance the genetic integrity of the fish within each river system. Consequently, the gametes produced from the limited number of adult salmon returning to each of these river systems are extremely valuable in terms of providing a sufficient number of offspring to continue the restoration effort. In the course of study, chronic symptoms of Bacterial Coldwater Disease, caused by Flavobacterium psychrophilum, were noted among a proportion of offspring that are propagated and stocked as smolts. Classical peduncle lesions and chronic mortality were associated with the affected fish. The disease was more pronounced in salmon reared in two-year rather than one-year smolt production cycles. Following the identification of these symptoms, the pathogen was shown to be the etiologic agent of mortality among yolk-sac fry in Heath incubators, associated with reductions in egg viability, and indicated to be transmitted by intra-ovum infection. The pathogen, therefore, has a significant role in the production of quality gametes and may be an extremely important factor in the post-stocking survival of salmon fry and smolts.
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U.S. Department of the Interior \|\| U.S. Geological Survey 11700 Leetown Road, Kearneysville, WV 25430, USA URL: http://www.lsc.usgs.gov Maintainer: lsc_webmaster@usgs.gov Last Modified: October 21, 2002 dwn Privacy Policy and Disclaimers \|\| FOIA \|\| Accessibility